1. Field of the Invention
The present invention relates to a handwritten character input device employed to input handwritten characters or handwritten instructions to a computer.
2. Description of Related Art
In input of a handwritten character, a stroke is drawn with a stylus pen on a tablet. The handwritten character is then recognized based upon strokes entered by a handwritten character input device into a computer. Examples of handwriting recognition methods are disclosed in Japanese Patent Publication No. 5-22949.
According to a conventional handwritten input device, a stroke error is detected only after the character is completed including the stroke error; and the stroke error is corrected by erasing the entire character and rewriting it. Further, the erasing of the character is managed by the user either by entering the command or selecting the command from the menu. To be concrete, in execution of the command-driven program, the user enters the command directing the erasure/rewrite of the character. In execution of the menu-driven program, the user selects the delete operation from the menu as well as designates the character including the stroke error so that the character will be erased immediately; or selects the eraser from the menu to convert the stylus pen into the eraser, and erases with tracing over the character with the eraser. As a further example, Japanese Patent Publication 2-113386 discloses a handwritten character input device whereby the character will be erased if it includes a stroke longer than the threshold value.
On the other hand, if no stroke error is found in the complete character, a character recognition unit accommodated inside of the handwritten character input device recognizes the character.
Thus, the conventional handwritten character input device executes the error correction only after the input of the character is completed. Consequently, it has the disadvantage of recognition error of the character caused by the uncorrected stroke error. That is, when two characters differ from each other only in one stroke, one of them may be misidentified as the other unless the stroke distinguishing them is drawn correctly. Taking two of English letters as an example, "E" is distinguished from "F" in one horizontal stroke at the end. We assume that the user, having "F" in mind, draws the horizontal stroke by mistake. In this case, "F" will be mistakenly recognized as "E", unless the stroke error is corrected immediately.
Furthermore, the conventional handwritten character input device has the disadvantage of laborious processes at erasing the data. That is, the ongoing input operation is forced to cease and the command directing the erasing operation is selected by the user.